U.S. patent number 4,649,262 [Application Number 06/694,151] was granted by the patent office on 1987-03-10 for heating cylinder device for a molding machine.
This patent grant is currently assigned to Omron Tateisi Electronics Co.. Invention is credited to Norio Yoshikawa.
United States Patent |
4,649,262 |
Yoshikawa |
March 10, 1987 |
Heating cylinder device for a molding machine
Abstract
This heating cylinder device for a molding machine includes a
cylinder member along the axial direction of which and within which
are defined several heating zones for material to be molded, each
of the heating zones being provided with a heater, wherein the
heating capacities and the thermal conductivities to the exterior
of the heating zones are suitably arranged so as to correspond to
the temperatures and operational performances required from the
heating zones. Each of the heaters may optionally surround the
portion of the cylinder member defining its heating zone. The
external diameter of the portion of the cylinder member defining
each of the heating zones may be varied according to the heat
capacity and temperature required therefrom; or, the portions of
the cylinder member between its portions defining the heating zones
may be substantially narrowed down as compared to its portions
defining the heating zones; or, each of the heaters may be buried
in the portion of the cylinder member defining its heating zone;
or, a plurality of layers of insulating material may be provided as
surrounding a plurality of the heating zones and the heaters
surrounding them. In the last case, these layers may be of
different thicknesses.
Inventors: |
Yoshikawa; Norio (Kyoto,
JP) |
Assignee: |
Omron Tateisi Electronics Co.
(Kyoto, JP)
|
Family
ID: |
27455456 |
Appl.
No.: |
06/694,151 |
Filed: |
January 23, 1985 |
Foreign Application Priority Data
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Jan 23, 1984 [JP] |
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59-10760 |
Mar 13, 1984 [JP] |
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59-35463[U]JPX |
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Current U.S.
Class: |
219/421; 219/424;
425/144 |
Current CPC
Class: |
B29C
45/74 (20130101); B29C 48/875 (20190201); B29C
48/83 (20190201); B29C 48/92 (20190201); B29C
2948/92895 (20190201); B29C 2948/92704 (20190201); B29C
48/03 (20190201) |
Current International
Class: |
B29C
47/82 (20060101); B29C 45/74 (20060101); B29C
45/72 (20060101); B29C 47/78 (20060101); B29C
47/92 (20060101); F27B 014/06 () |
Field of
Search: |
;219/214,388,421,424,521
;165/87 ;222/146.5 ;425/549,143,144,145 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1167008 |
|
Apr 1964 |
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DE |
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1572514 |
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Jul 1980 |
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GB |
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Other References
Die Technick des Strangpressens, Jean Peynichou ("Industries des
Plastiques Modernes", Paris), 1958, vol. I, pp. 9-11..
|
Primary Examiner: Goldberg; E. A.
Assistant Examiner: Walberg; Teresa J.
Attorney, Agent or Firm: Stevens, Davis, Miller &
Mosher
Claims
What is claimed is:
1. A heating cylinder device for a molding machine, said device
comprising a thermally conductive cylinder member including a
central axial hole and a plurality of heating zones disposed
axially along said cylinder member, each of said heating zones
comprising a heater and means cooperating with said heater for
individually controlling a temperature within a portion of said
central axial hole disposed within a respective said heating zone
to correspond to a predetermined temperature and operational
performance desired for a respective said heating zone, the
external diameter of said cylinder member containing said heating
zones being stepwise varied to define said heating zones with each
of said zones having a different external diameter for said
cylinder member.
2. A heating cylinder device according to claim 1, wherein each of
said heaters surrounds the portion of said cylinder member defining
its said heating zone.
3. A heating cylinder device according to claim 1 or claim 2,
wherein the portions of said cylinder member between its said
portions defining said heating zones are substantially narrowed
down as compared to its said portions defining said heating
zones.
4. A heating cylinder device according to claim 3, wherein said
portions of said cylinder member between its said portions defining
said heating zones are formed as grooves between its said portions
defining said heating zones.
5. A heating cylinder device according to claim 3, further
comprising insulating members fitted over said portions of said
cylinder member between its said portions defining said heating
zones.
6. A heating cylinder device according to claim 1 or claim 2,
wherein each of said heaters is buried in the portion of said
cylinder member defining its said heating zone.
7. A heating cylinder device according to claim 1 or claim 2,
further comprising a layer of insulating material surrounding one
of said heating zones and said heater surrounding it.
8. A heating cylinder device according to claim 1 or claim 2,
further comprising a plurality of layers of insulating material
surrounding a plurality of said heating zones and said heaters
surrounding them.
9. A heating cylinder device according to claim 8, wherein the
layers of said insulating material surrounding different ones of
said heating zones and said heaters are of different
thicknesses.
10. A heating cylinder device according to claim 1, wherein said
cylinder member has a material inlet end and a material outlet end,
and the external diameter of said cylinder member progressively
increases stepwise for a predetermined number of heating zones in a
direction from said inlet end to said outlet end.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a heating cylinder device for
melting resin material in a molding machine such as an injection
molding machine or an extruder or the like which performs mold
forming using such resin as a material, and in particular to such a
heating cylinder device which can more effectively accomplish
steady and uniform heating up of such resin material.
In the prior art with regard to this sort of heating cylinder
device for a molding machine, demands are nowadays constantly being
made for shortening of the injection cycle, in order to improve
productivity. Further, it is also very desirable to reduce the
power consumption of the heating means for the resin, which
typically accounts for about a third of the total power consumption
of the injection molding machine. Reduction of the power required
for setting up the machine and bringing its various parts to
appropriate operating temperatures is effective for meeting this
end. And yet further it is a constant requirement to improve the
precision of the molded products made by the molding machine, which
entails as accurate control of heating of the resin material as
possible. Accordingly, proper heat management of the heating
cylinder device for the resin is crucial for meeting these
needs.
Now, in the prior art, such a heating cylinder device typically has
had a plurality of heating zones arranged, and has basically been
shaped as a uniform hollow cylinder, with a plurality of annular
band shaped heaters arranged longitudinally around its outer
surface along the lengthwise direction, each such heater being
wrapped around one of the heating zones. These heaters are
energized in such appropriate amounts as to keep the successive
heating zones at appropriate temperatures to ensure proper heating
up of the resin material to be molded, as such resin material is
progressively moved down along the central hole of the hollow
heating cylinder device by the action of a plunger or the like.
Thus, the heat management for these heating zones is performed.
However, the problems with such a prior art type of heating
cylinder device are as follows.
First, because the thickness of the heating cylinder has been
uniform for each of the heating zones, thermal interferences tend
to develop between neighboring ones of the heating zones, in
addition to the interferences arising from external sources such as
changes in the ambient temperature, fluctuations in the system due
to the motion of the resin material which is being heated up,
changes in the temperature of the resin material, dissipation of
heat in injecting the resin material, and so on. Accordingly
accurate temperature control of the resin becomes very difficult.
Further, because the thickness of the heating cylinder has been
uniform for each of the heating zones, each of these heating zones
has approximately the same heat capacity, and in view of the
different temperatures up to which these zones are required to be
heated this causes difficulties in heating control.
Secondly, because each heating zone as defined along the axis of
the heating cylinder device is contiguous to the next, and the
heating cylinder device is constructed basically as a uniform
hollow cylinder, the abovementioned thermal interferences which
tend to develop between neighboring ones of the heating zones are
very strong, and present a substantial obstacle to the proper heat
control of the various heating zones.
Thirdly, because the thickness of the walls of the heating cylinder
device, in other words the distance between its outer
circumferential surface on which, in the above outlined prior art,
the band shaped heaters are mounted, and its inner hole in which
the resin is flowing, is very substantial, a time delay occurs in
the transfer of heat from the heaters to the resin, and accordingly
precise temperature control of the resin becomes very difficult,
and fluctuations in the system, such as alterations in the ambient
temperature, changes in the flow speed of the resin and in the
temperature at which said resin is supplied to the heating cylinder
device, and changes in the dissipation of heat that occurs when
injecting the resin, cause great problems with regard to
temperature control, because of the lack of responsiveness of the
system.
Fourthly and lastly, because the thermal capacity of each of the
heating zones is approximately the same, and because the resistance
to heat flow from each of the heating zones to the outside is
approximately the same, this further causes thermal interferences
between the neighboring heating zones to occur.
SUMMARY OF THE INVENTION
Accordingly, it is the primary object of the present invention to
provide a heating cylinder device for a molding machine which
avoids the above outlined disadvantages.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which can keep the
injection cycle of the machine short.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which can improve
productivity of the machine.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which reduces the
power consumption as much as practicable.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which reduces
operational cost.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which reduces the
cost of the finished products.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which can improve the
temperature control of the resin.
It is a further object of the present invention to provide such a
heating cylinder device for a molding machine which can improve the
responsiveness of the temperature control.
It is a yet further object of the present invention to provide such
a heating cylinder device for a molding machine which promotes the
production of more precise finished molded products.
It is a yet further object of the present invention to provide such
a heating cylinder device for a molding machine which provides
proper heat management.
It is a yet further object of the present invention to provide such
a heating cylinder device for a molding machine which keeps the
thermal interference between neighboring ones of heating zones
thereof as low as possible.
It is a yet further object of the present invention to provide such
a heating cylinder device for a molding machine which keeps the
thermal interference from outside sources as low as possible.
It is a yet further object of the present invention to provide such
a heating cylinder device for a molding machine which minimizes
fluctuations in the system due to the motion of the resin material
which is being heated up, changes in the temperature of the resin
material, dissipation of heat in injecting the resin material, and
so on.
According to the most general aspect of the present invention,
these and other objects are accomplished by a heating cylinder
device for a molding machine, comprising a cylinder member along
the axial direction of which and within which are defined a
plurality of heating zones for material to be molded, each of said
heating zones being provided with a heater, wherein the heating
capacities and the thermal conductivities to the exterior of said
heating zones are suitably arranged so as to correspond to the
temperatures and operational performances required from said
heating zones.
According to such a structure, as will be particularly explained
with regard to particular embodiments of the present invention,
there is provided a heating cylinder device for a molding machine
which can keep the injection cycle of the machine short, thus
improving the productivity of the machine and reducing the cost of
operation and the cost of the finished products. Further, the power
consumption is reduced as much as practicable, and the temperature
control of the resin is improved, and the responsiveness of the
temperature control is also improved. Thus, this heating cylinder
device for a molding machine minimizes fluctuations in the system
due to the motion of the resin material which is being heated up,
changes in the temperature of the resin material, dissipation of
heat in injecting the resin material, and so on. Thereby, this
heating cylinder device for a molding machine promotes the
production of more precise finished molded products, by providing
proper heat management by keeping the thermal interference between
neighboring ones of heating zones thereof as low as possible, as
well as by keeping the thermal interference from outside sources as
low as possible.
As a useful specialization of the above defined concept, these and
other objects are yet more particularly and concretely accomplished
by a heating cylinder device as described above, wherein each of
said heaters surrounds the portion of said cylinder member defining
its said heating zone.
Further, according to one particular constructional aspect of the
present invention, these and other objects may be more particularly
and concretely accomplished by a heating cylinder device of either
of the types described above, wherein the external diameter of the
portion of said cylinder member defining each of said heating zones
is varied according to the heat capacity and temperature required
therefrom; or, according to another particular constructional
aspect of the present invention, these and other objects may be
more particularly and concretely accomplished by a heating cylinder
device of either of the types described above, wherein the portions
of said cylinder member between its said portions defining said
heating zones are substantially narrowed down as compared to its
said portions defining said heating zones; or, according to another
particular constructional aspect of the present invention, these
and other objects may be more particularly and concretely
accomplished by a heating cylinder device of either of the types
described above, wherein each of said heaters is buried in the
portion of said cylinder member defining its said heating zone; or,
according to yet another particular constructional aspect of the
present invention, these and other objects may be more particularly
and concretely accomplished by a heating cylinder device of either
of the types described above, further comprising one or a plurality
of layers of insulating material surrounding one or a plurality of
said heating zones and said heaters surrounding them.
According to these various particular structural concepts, the
present invention may be concretely realized in an appropriate form
for the particular application.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be shown and described with
reference to the preferred embodiments thereof, and with reference
to the illustrative drawings. It should be clearly understood,
however, that the description of the embodiments, and the drawings,
are all of them given purely for the purposes of explanation and
exemplification only, and are none of them intended to be
limitative of the scope of the present invention in any way, since
the scope of the present invention is to be defined solely by the
legitimate and proper scope of the appended claims. In the
drawings, like parts and spaces and so on are denoted by like
reference symbols in the various figures thereof; in the
description, spatial terms are to be everywhere understood in terms
of the relevant figure; and:
FIG. 1 is a side view of an injection molding machine incorporating
a schematic heating cylinder device according to the present
invention, this figure being applicable to any of the four
preferred embodiments of the present invention which will be
disclosed herein;
FIG. 2 is a sectional view through a heating cylinder device, such
as may be fitted to the injection molding machine of FIG. 1,
according to a first preferred embodiment of the present invention,
taken in a sectional plane containing the axis of said heating
cylinder device;
FIG. 3 is a schematic block diagram, showing a possible
construction for a control system for the heating control of five
heating zones of the heating cylinder device of FIG. 2, including a
central processing unit or CPU;
FIG. 4 is a schematic control diagram for showing the processes of
temperature control for the five heating zones of the heating
cylinder device of FIG. 2 as performed by the CPU of FIG. 3;
FIG. 5 is similar to FIG. 2, and shows a sectional view through a
heating cylinder device, such as may be fitted to the injection
molding machine of FIG. 1, according to a second preferred
embodiment of the present invention, again taken in a sectional
plane containing the axis of said heating cylinder device;
FIG. 6 is similar to FIGS. 2 and 5, and shows a sectional view
through a heating cylinder device, such as may be fitted to the
injection molding machine of FIG. 1, according to a third preferred
embodiment of the present invention, again taken in a sectional
plane containing the axis of said heating cylinder device; and
FIG. 7 is similar to FIGS. 2, 5, and 6, and shows a sectional view
through a heating cylinder device, such as may be fitted to the
injection molding machine of FIG. 1, according to a fourth
preferred embodiment of the present invention, again taken in a
sectional plane containing the axis of said heating cylinder
device.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will now be described with reference to the
preferred embodiments thereof, and with reference to the appended
drawings. FIG. 1 is a side view of an injection molding machine,
denoted generally by the reference numeral 10, which is for molding
resin, and which incorporates a heating cylinder device 12
according to the present invention which may be one according to
the first preferred embodiment of the present invention. In more
detail, the injection molding machine 10 comprises a hopper 11 for
charging the resin, the aforementioned heating cylinder device 12,
a screw drive device 13 for rotatively driving a screw piston 20
incorporated in said heating cylinder device 12 which will be
described later for injecting the molten resin, and a movable plate
drive device 17 for removing the molded products by opening and
closing a metallic die 16 which is mounted between a fixed plate 14
and a laterally movable plate 15.
In FIG. 2, there is shown a sectional view of this heating cylinder
device 12 according to the first preferred embodiment of the
present invention, taken in a sectional plane containing the axis
of said heating cylinder device. The device 12 is generally formed
in a cylindrical shape with a central axial hole 19 formed through
a cylinder wall portion 18, and a screw piston 20 mentioned above
is fitted in said central axial hole 19, so as when rotated in a
certain direction by the aforementioned screw drive device 13 to
move to the left in the figure into said hole 19 so as to apply
compression force to resin in said hole 19, and so as when rotated
in the opposite direction to said certain direction to be moved to
the right in the figure and to be withdrawn out of said hole 19.
When said screw piston 20 is thus withdrawn from the hole 19 to a
position beyond a given position, resin charged in the hopper 11
can travel downwards into the hole 19 to recharge the heating
cylinder device 12. A nozzle 21 is provided at the opposite end
(the left end) of the heating cylinder device 12 from the hopper 11
(which is at the right end). Thus, as the screw piston 20 is
alternately rotated in said certain direction and in the opposite
direction to said certain direction, it is alternately forced into
the hole 19 and withdrawn therefrom, thus alternately compressing
resin in said hole 19 and forcing it out through the nozzle 21, and
recharging said hole 19 with fresh resin from the hopper 11.
In the heating cylinder device 12, there are altogether defined
five heating zones, designated as Z1 through Z5, and axially spaced
along the axis of said heating cylinder device 12 from the right to
the left as seen in FIG. 2, i.e. from the end thereof at which the
hopper 12 is provided to the end thereof at which the nozzle 21 is
provided. Around each of these heating zones Z1 through Z5 there is
fitted a corresponding heater H1 through H5, which is formed as a
band extending right around the cylinder of the heating cylinder
device 12, and in the inner wall portion of the heating cylinder
device 12, in each of said heating zones Z1 through Z5, there is
fitted a corresponding thermocouple T1 through T5.
In detail, the first heating zone Z1 is the portion of the heating
cylinder device 12 into which the resin is supplied from the hopper
11, and is heated by the heater H1 and is also water cooled so that
the resin may be supplied from the hopper 11 without any risk of
its surface being melted. And the thermocouple T1 detects the
temperature in this first heating zone Z1. The second heating zone
Z2 is a portion of the heating cylinder device 12 in which the
resin is, next, heated up substantially only by the heater H2, and
the thermocouple T2 detects the temperature in this second heating
zone Z2. The third heating zone Z3 is a portion of the heating
cylinder device 12 in which the resin is, next, heated up both by
the heater H3 and by the frictional heat generated by the rotation
of and by the compression effect generated by the screw piston 20;
and the thermocouple T3 detects the temperature in this third
heating zone Z3. The fourth heating zone Z4 is a reservoir in which
the resin material to be injected is received for a certain time
interval before being injected, and is required to be kept at a
certain high temperature; in this portion of the heating cylinder
device 12, the resin is heated up by the heater H4, and the
thermocouple T4 detects the temperature in this fourth heating zone
Z4. And the fifth heating zone Z5, which is just before the nozzle
21, is a portion of the heating cylinder device 12 in which the
resin is particularly subject to disturbance of its temperature by
external influences such as the heat capacity of the metallic die
16 and the atmosphere; and, in order to eliminate such external
influence, the resin in this fifth heating zone Z5 is kept hot by
the heater H5, and the thermocouple T5 detects the temperature in
this fifth heating zone Z5.
Now, particularly according to the particularly specialized
inventive concept of this first preferred embodiment of the present
invention, the wall portion 18 of the heating cylinder device 12 is
structured, not as in the prior art described above as a uniform
cylinder of the same inner and outer diameters along its
longitudinal length, but with the same inner diameter along its
longitudinal length and with an outer diameter which increases in
steps from the first heating zone Z1 to the second heating zone Z2,
from the second heating zone Z2 to the third heating zone Z3, and
from the second heating zone Z3 to the fourth heating zone Z4. And
the outer diameter of the wall portion 18 of the heating cylinder
device 12 at the fifth heating zone Z5 is much smaller than at all
the other heating zones Z1 through Z4. Thus, the portions of the
wall portion 18 which define the heating zones Z1 through Z5 are
each of thickness appropriate to define a cylinder portion with
heat capacity corresponding to the heating temperature required for
said heating zone. In other words, the portions of the wall portion
18 of the heating cylinder device 12 which define the first heating
zone Z1 and the fifth heating zone Z5 are thin, because the
temperature control provided by the heaters H1 and H5 for these two
heating zones Z1 and Z5 is required to be transferred very
accurately and quickly to the resin, and accordingly the heat
capacities of these portions of the wall portion 18 are kept low;
while on the other hand the portions of said wall portion 18 of the
heating cylinder device 12 which define the second, third, and
fourth heating zones Z2 through Z4 are thicker, because heating
temperatures required for these heating zones Z2 through Z4 are
higher and accordingly it is beneficial to make the heat capacities
of these portions of the wall portion 18 greater. In particular,
the thickness of the portion of the wall portion 18 which defines
the fourth heating zone Z4, which is required to be kept at a
certain relatively high temperature, is made the thickest, so as to
maximize the heat capacity of this portion of the wall portion
18.
In FIG. 3, there is schematically shown in block diagram form a
possible exemplary construction for the control system for the
heating control of the five heating zones Z1 through Z5; although
this control system does not form part of the present invention in
the strict sense, nevertheless it is shown for the purposes of
explanation, because its function is relevant. In this figure, the
reference numeral 22 denotes a CPU (central processing unit) which
via a bus communicates with an operation panel 23, a power output
control unit 24, and a temperature input unit 25. The power output
control unit receives signals from the CPU 22, and based upon their
values controls the supply of power (in an ON and OFF fashion or a
fashion of bang bang control) to the five band shaped heaters H1
through H5 for the five heating zones Z1 through Z5 respectively.
The temperature input unit 25 receives supply of signals from the
five thermocouples T1 through T5 for the five heating zones Z1
through Z5 respectively, and based upon the values of said signals
(which are representative of the temperatures in said heating zones
Z1 through Z5) outputs signals to the CPU 22. The operation panel
23 allows the setting up of target values for the temperatures for
the five heating zones Z1 through Z5 individually, and based upon
the values of said set up target values outputs appropriate signals
to the CPU 22. CPU 22 operates according to various programs stored
in its internal memory to control the aforementioned circuits and
others not shown, thereby recording and reading out necessary data
and performing calculations of various parameters associated with
the temperature control of the five heating zones Z1 through
Z5.
In FIG. 4, a schematic control diagram for the temperature control
for the heating zones Z1 through Z5 as performed by the CPU 22 is
shown. In the case of the shown exemplary construction and
operation, which are not intended to be limitative of the present
invention, the processes of control of the temperatures of the
first through the third heating zones Z1 through Z3 are performed
by adaptive control, while on the other hand the processes of
control of the temperatures of the fourth and the fifth heating
zones Z4 and Z5 are performed by I-PD control.
The reference numeral 26 denotes an adaptive control unit for
performing this adaptive control of the temperatures of the first
through the third heating zones Z1 through Z3. This adaptive
control unit 26 sets up a plurality of parameters for the first
through the third heating zones Z1 through Z3, and, when the target
values ts1 through ts3 for the temperatures of said first through
the third heating zones Z1 through Z3 are inputted as set up on the
operation panel 23, selects the parameters which correspond to
these target values ts1 through ts3 so as to perform temperature
control of the heating temperatures of the band heaters H1 through
H3 with certain manipulated variables Un. The calorific values Gn
of the heating zones Z1 through Z3 are detected by the
corresponding thermocouples T1 through T3 respectively, or in other
words the temperatures of the corresponding parts of the inner wall
portion of the wall portion 18 of the heating cylinder device 12
are detected, and the controlled variables tn are inputted into the
adaptive control unit 26. But these controlled variables are
contaminated by external influences and interferences. Therefore,
the adaptive control unit 26 evaluates the parameters according to
the manipulated variables Un and the controlled variables tn, or in
other words evaluates whether the temperature control is being
performed with the optimum parameters among other parameters
(because it should be remembered that a plurality of such
parameters are prepared in advance); and the evaluated variables An
thus prepared are fed back to the adaptive control unit 26 for
temperature controlling the heating zones Z1 through Z3 with the
optimum parameters.
Thus, by adapting the outer diameter of the wall portion 18 of the
heating cylinder device 12 to the particular requirements of each
of the three heating zones Z1 through Z3, according to their heat
capacities, in other words by reducing the outer diameter of said
wall portion 18 in consideration of the desirability of
responsiveness of the temperature control, in addition to
temperature controlling the respective heating zones Z1 through Z3,
the influences of thermal interferences between the heating zones
Z1 through Z3 may be largely eliminated, and fluctuations of the
temperature of the resin which is to be forwarded to the fourth
heating zone Z4 may be kept minimal.
The reference numeral 27 denotes an IP-D control unit for
performing the IP-D control of the temperatures of the fourth and
fifth heating zones Z4 and Z5. This IP-D control unit 27 is set up
with a single parameter for the temperature control of each of the
fourth and fifth heating zones Z4 and Z5, and, when the target
values ts4 and ts5 for the temperatures of said fourth and fifth
heating zones Z4 and Z5 are inputted as set up on the operation
panel 23, performs temperature control of the heating temperatures
of the band heaters H2 and H5 for these heating zones Z4 and Z5
with the controlled variables Un for each of the parameters.
Because the calorific values of the heating zones Z4 and Z5 are
detected by the respective thermocouples T4 and T5, and the
detected variables tn are subject to some admixture of external
influences and interferences, these detected variables tn are fed
back to the IP-D control unit 27 for temperature control.
Thus, by adapting the outer diameter of the wall portion 18 of the
heating cylinder device 12 to the particular requirement of the
fourth heating zone Z4, according to its heat capacity, in other
words by increasing the outer diameter of said wall portion 18 in
consideration of the desirability of increasing its thermal
capacity, in addition to temperature controlling the heating zones
Z4 and Z5, the temperature of the resin material to be injected
through the nozzle 21 is made uniform and is stabilized at a fixed
temperature value, and high precision molding is made possible. As
for the thermal interference G between the first through the third
heating zones Z1 through Z3 and the fourth and the fifth heating
zones Z4 and Z5, it is eliminated by calculating the deviations Bn
and by feeding them back to the controller.
Thus, according to the present invention, the thermal interference
between the neighboring ones of the heating zones Z1 through Z5 is
kept minimal, because the outer diameters of the relevant parts of
the wall portion 18 of the heating cylinder device 12 are adapted
to the particular requirements of these heating zones Z1 through
Z5, so as to provide heating capacities corresponding to the
heating temperatures of the zones Z1 through Z5.
Thus, according to this first preferred embodiment of the present
invention, there is provided a heating cylinder device for a
molding machine which can keep the injection cycle of the machine
short, thus improving the productivity of the machine and reduces
the cost of operation and thus the cost of the finished products.
Further, the power consumption is reduced as much as practicable,
and the temperature control of the resin is improved, and the
responsiveness of the temperature control is also improved. Thus,
this heating cylinder device for a molding machine minimizes
fluctuations in the system due to the motion of the resin material
which is being heated up, changes in the temperature of the resin
material, dissipation of heat in injecting the resin material, and
so on. Thereby, this heating cylinder device for a molding machine
promotes the production of more precise finished molded products,
by providing proper heat management by keeping the thermal
interference between neighboring ones of heating zones thereof as
low as possible, as well as by keeping the thermal interference
from outside sources as low as possible.
In FIG. 5, there is shown a sectional view of a heating cylinder
device 12 according to the second preferred embodiment of the
present invention, taken in a fashion similar to FIG. 2 in a
sectional plane containing the axis of said heating cylinder
device; in FIG. 5, reference symbols like to those of FIGS. 1 and 2
relating to the first preferred embodiment denote like parts and
zones. This heating cylinder device 12 is for being fitted into an
injection molding machine like the machine 10 shown in FIG. 1
relating to the first preferred embodiment, comprising a hopper for
charging the resin, the heating cylinder device 12, a screw drive
device for rotatively driving a screw piston 20 incorporated in
said heating cylinder device 12 for injecting the molten resin, and
a movable plate drive device for removing the molded products by
opening and closing a metallic die which is mounted between a fixed
plate and a laterally movable plate; this machine is not
particularly shown in the figures, because its construction may be
substantially identical to that of the FIG. 1 machine.
The heating cylinder device 12, in this second preferred
embodiment, again is generally formed in a cylindrical shape with a
central axial hole 19 formed through a cylinder wall portion 18,
and with a screw piston 20 mentioned above fitted in said central
axial hole 19, so as when rotated in a certain direction by the
aforementioned screw drive device 13 to move to the left in the
figure into said hole 19 so as to apply compression force to resin
in said hole 19, and so as when rotated in the opposite direction
to said certain direction to be moved to the right in the figure
and to be withdrawn out of said hole 19. When said screw piston 20
is thus withdrawn from the hole 19 to a position beyond a certain
position, resin charged in the hopper 11 can travel downwards into
the hole 19 to recharge the heating cylinder device 12. A nozzle 21
is provided at the opposite end (the left end) of the heating
cylinder device 12 from the hopper 11 (which is at the right end).
Thus, as the screw piston 20 is alternately rotated in said certain
direction and in the opposite direction to said certain direction,
it is alternately forced into the hole 19 and withdrawn therefrom,
thus alternately compressing resin in said hole 19 and forcing it
out through the nozzle 21, and recharging said hole 19 with fresh
resin from the hopper 11.
In the heating cylinder device 12, as before in the FIG. 2 device,
there are altogether defined five heating zones, designated as Z1
through Z5, and axially spaced along the axis of said heating
cylinder device 12 from the right to the left as seen in FIG. 5,
i.e. from the end thereof at which the hopper 11 is provided to the
end thereof at which the nozzle 21 is provided. Around each of
these heating zones Z1 through Z5 there is fitted a corresponding
heater H1 through H5, which is formed as a band extending right
around the cylinder of the heating cylinder device 12, and in the
inner wall portion of the heating cylinder device 12, in each of
said heating zones Z1 through Z5, there is again fitted a
corresponding thermocouple T1 through T5.
In detail, again, the first heating zone Z1 is the portion of the
heating cylinder device 12 into which the resin is supplied from
the hopper 11, and is heated by the heater H1 and is also water
cooled so that the resin may be supplied from the hopper 11 without
any risk of its surface being melted. And the thermocouple T1
detects the temperature in this first heating zone Z1. The second
heating zone Z2 is a portion of the heating cylinder device 12 in
which the resin is, next, heated up substantially only by the
heater H2, and the thermocouple T2 detects the temperature in this
second heating zone Z2. The third heating zone Z3 is a portion of
the heating cylinder device 12 in which the resin is, next, heated
up both by the heater H3 and by the frictional heat generated by
the rotation of and by the compression effect generated by the
screw piston 20; and the thermocouple T3 detects the temperature in
this third heating zone Z3. The fourth heating zone Z4 is a
reservoir in which the resin material to be injected is received
for a certain time interval before being injected, and is required
to be kept at a certain high temperature; in this portion of the
heating cylinder device 12, the resin is heated up by the heater
H4, and the thermocouple T4 detects the temperature in this fourth
heating zone Z4. And the fifth heating zone Z5, which is just
before the nozzle 21, is a portion of the heating cylinder device
12 in which the resin is particularly subject to disturbance of its
temperature by external influences such as the heat capacity of the
metallic die 16 and the atmosphere; and, in order to eliminate such
external influencese, the resin in this fifth heating zone Z5 is
kept hot by the heater H5, and the thermocouple T5 detects the
temperature in this fifth heating zone Z5.
Now, particularly according to the particularly specialized
inventive concept of this second preferred embodiment of the
present invention, the wall portion 18 of the heating cylinder
device 12 is structured, not as in the prior art described above as
a uniform cylinder of the same inner and outer diameters along its
longitudinal length, but with annular circumferentially extending
grooves 38 spaced apart along its longitudinal length. However, in
contrast to the first preferred embodiment described above, the
outer diameters of the parts of the wall portion 18 of the heating
cylinder device 12 which define the first heating zone Z1, the
second heating zone Z2, the third heating zone Z3, and the fourth
heating zone Z4 are all substantially the same; while as before the
outer diameter of the wall portion 18 of the heating cylinder
device 12 at the fifth heating zone Z5 is much smaller than at all
the other heating zones Z1 through Z4. Thus, the portions of the
wall portion 18 which define the heating zones Z1 through Z4 are
each of approximately the same thickness, in this second preferred
embodiment. However, by the provision of the annular grooves 38,
the heat capacities of the portions of the wall portion 18 of the
heating cylinder device 12 in between those portions thereof which
define the first heating zone Z1, the second heating zone Z2, the
third heating zone Z3, and the fourth heating zone Z4 are made to
be very much lower than the heat capacities of said portions which
define said heating zones Z1 through Z4, and further the heat
transmission capacities of said in between portions are made to be
very low; so that, substantially, the portions of the wall portion
18 of the heating cylinder device 12 in between those portions
thereof which define the first heating zone Z1, the second heating
zone Z2, the third heating zone Z3, and the fourth heating zone Z4
are thermally completely isolated from one another. This thermal
isolation is further promoted by the further constructional detail
that annular ring members 29 made of a thermally insulating
material are fitted into the grooves 38, so as further to hamper
thermal transfer by conduction across said grooves 38 between
adjoining ones of the heating zones Z1 through Z4, and so as
further to substantially prevent heat transfer by radiation and by
convection between said heating zones Z1 through Z4. It should be
noted, however, that these insulating annular ring members 29 are
not strictly necessary for implementing the concept of this second
preferred embodiment of the present invention, in its most basic
form, and may be omitted in some cases.
This heating cylinder device 12 according to the second preferred
embodiment of the present invention may be controlled by a control
system similar to that described above with reference to FIGS. 3
and 4 with respect to the first preferred embodiment; details are
omitted herein in the interests of brevity of description.
Although in the above FIG. 5 relating to this shown second
preferred embodiment the widths of the grooves 38 are shown as
being substantially the same, it would be possible to vary the
widths of these grooves 38, as a further refinement of the
inventive concept of said second preferred embodiment.
Thus, by providing the grooves 38 as thermally separating the
heating zones Z1 through Z4 from one another, and optionally by
further providing the insulating annular rings 29 as located
therein, in addition to temperature controlling the respective
heating zones Z1 through Z3, the influences of thermal
interferences between the heating zones Z1 through Z4 may be
largely eliminated, and fluctuations of the temperature of the
resin which is to be forwarded to the fifth heating zone Z5 may be
kept minimal.
Thus, also according to this second preferred embodiment of the
present invention, there is provided a heating cylinder device for
a molding machine which can keep the injection cycle of the machine
short, thus improving the productivity of the machine and reduces
the cost of operation and thus the cost of the finished products.
Further, the power consumption is reduced as much as practicable,
and the temperature control of the resin is improved, and the
responsiveness of the temperature control is also improved. Thus,
this heating cylinder device for a molding machine minimizes
fluctuations in the system due to the motion of the resin material
which is being heated up, changes in the temperature of the resin
material, dissipation of heat in injecting the resin material, and
so on. Thereby, this heating cylinder device for a molding machine
promotes the production of more precise finished molded products,
by providing proper heat management by keeping the thermal
interference between neighboring ones of heating zones thereof as
low as possible, as well as by keeping the thermal interference
from outside sources as low as possible.
In FIG. 6, there is shown a sectional view of a heating cylinder
device 12 according to the third preferred embodiment of the
present invention, taken in a fashion similar to FIGS. 2 and 5 in a
sectional plane containing the axis of said heating cylinder
device; in FIG. 6, reference symbols like to those of FIGS. 1 and 2
relating to the first preferred embodiment and FIG. 5 relating to
the second preferred embodiment denote like parts and zones. This
heating cylinder device 12 again is for being fitted into an
injection molding machine like the machine 10 shown in FIG. 1
relating to the first preferred embodiment, comprising a hopper for
charging the resin, the heating cylinder device 12, a screw drive
device for rotatively driving a screw piston 20 incorporated in
said heating cylinder device 12 for injecting the molten resin, and
a movable plate drive device for removing the molded products by
opening and closing a metallic die which is mounted between a fixed
plate and a laterally movable plate; again, this machine is not
particularly shown in the figures, because its construction may be
substantially identical to that of the FIG. 1 machine.
The heating cylinder device 12, in this third preferred embodiment,
again is generally formed in a cylindrical shape with a central
axial hole 19 formed through a cylinder wall portion 18, and with a
screw piston 20 mentioned above fitted in said central axial hole
19, so as when rotated in a certain direction by the aforementioned
screw drive device 13 to move to the left in the figure into said
hole 19 so as to apply compression force to resin in said hole 19,
and so as when rotated in the opposite direction to said certain
direction to be moved to the right in the figure and to be
withdrawn out of said hole 19. When said screw piston 20 is thus
withdrawn from the hole 19 to a position beyond a certain position,
resin charged in the hopper 11 can travel downwards into the hole
19 to recharge the heating cylinder device 12. A nozzle 21 is
provided at the opposite end (the left end) of the heating cylinder
device 12 from the hopper 11 (which is at the right end). Thus, as
the screw piston 20 is alternately rotated in said certain
direction and in the opposite direction to said certain direction,
it is alternately forced into the hole 19 and withdrawn therefrom,
thus alternately compressing resin in said hole 19 and forcing it
out through the nozzle 21, and recharging said hole 19 with fresh
resin from the hopper 11.
In the heating cylinder device 12, as before in the FIG. 2 and FIG.
5 devices, there are altogether defined five heating zones,
designated as Z1 through Z5, and axially spaced along the axis of
said heating cylinder device 12 from the right to the left as seen
in FIG. 6, i.e. from the end thereof at which the hopper 12 is
provided to the end thereof at which the nozzle 21 is provided.
Around each of these heating zones Z1 through Z5 there is fitted a
corresponding heater H1 through H5, and in the inner wall portion
of the heating cylinder device 12, in each of said heating zones Z1
through Z5, there is again fitted a corresponding thermocouple T1
through T5.
In detail, again, the first heating zone Z1 is the portion of the
heating cylinder device 12 into which the resin is supplied from
the hopper 11, and is heated by the heater H1 and is also water
cooled so that the resin may be supplied from the hopper 11 without
any risk of its surface being melted. And the thermocouple T1
detects the temperature in this first heating zone Z1. The second
heating zone Z2 is a portion of the heating cylinder device 12 in
which the resin is, next, heated up substantially only by the
heater H2, and the thermocouple T2 detects the temperature in this
second heating zone Z2. The third heating zone Z3 is a portion of
the heating cylinder device 12 in which the resin is, next, heated
up both by the heater H3 and by the frictional heat generated by
the rotation of and by the compression effect generated by the
screw piston 20; and the thermocouple T3 detects the temperature in
this third heating zone Z3. The fourth heating zone Z4 is a
reservoir in which the resin material to be injected is received
for a certain time interval before being injected, and is required
to be kept at a certain high temperature; in this portion of the
heating cylinder device 12, the resin is heated up by the heater
H4, and the thermocouple T4 detects the temperature in this fourth
heating zone Z4. And the fifth heating zone Z5, which is just
before the nozzle 21, is a portion of the heating cylinder device
12 in which the resin is particularly subject to disturbance of its
temperature by external influences such as the heat capacity of the
metallic die 16 and the atmosphere; and, in order to eliminate such
external influencese, the resin in this fifth heating zone Z5 is
kept hot by the heater H5, and the thermocouple T5 detects the
temperature in this fifth heating zone Z5.
Now, as in the second preferred embodiment described above, the
wall portion 18 of the heating cylinder device 12 is structured
(however not with any annular circumferentially extending grooves
spaced apart along its longitudinal length) with the outer
diameters of the parts of the wall portion 18 of the heating
cylinder device 12 which define the first heating zone Z1, the
second heating zone Z2, the third zone Z3, and the fourth heating
zone Z4 all being substantially the same; while as before the outer
diameter of the wall portion 18 of the heating cylinder device 12
at the fifth heating zone Z5 is much smaller than at all the other
heating zones Z1 through Z4. Thus, the portions of the wall portion
18 which define the heating zones Z1 through Z4 are each of
approximately the same thickness, in this third preferred
embodiment. However, particularly according to the particularly
specialized inventive concept of this third preferred embodiment of
the present invention, while the fifth heater H5 is as before
formed as a band extending right around the cylinder of the heating
cylinder device 12, the other four heaters H1 through H4, although
still band shaped, are now buried deep within the wall portion 18
of said heating cylinder device 12. In other words, these heaters
H1 through H4 are arranged to be as close in the radial direction
to the interior hole 19 of the heating cylinder device 12 as
possible, i.e. as close to the molten resin passing through said
interior hole 19 as possible. A band 28 of insulating material is
wrapped around the part of the wall portion 18 of the heating
cylinder device 12 which defines the fourth heating zone Z4, for
providing greater heat capacity and better insulating
performance.
This heating cylinder device 12 according to the third preferred
embodiment of the present invention may be controlled by a control
system similar to that described above with reference to FIGS. 3
and 4 with respect to the first preferred embodiment; details are
omitted herein in the interests of brevity of description.
Thus, by providing the heaters H1 through H4 as buried within the
wall portion 18 of said heating cylinder device 12, and as close in
the radial direction to the interior hole 19 of the heating
cylinder device 12 as possible, i.e. as close to the molten resin
passing through said interior hole 19 as possible, thermal
transmission from said heaters H1 to H4 to the molten resin
material is made as easy as practicable, and the responsiveness of
the control system is improved, whereby fluctuations of the
temperature of the resin which is to be forwarded to the fifth
heating zone Z5 may be kept minimal.
Thus, also according to this third preferred embodiment of the
present invention, there is provided a heating cylinder device for
a molding machine which can keep the injection cycle of the machine
short, thus improving the productivity of the machine and reduces
the cost of operation and thus the cost of the finished products.
Further, the power consumption is reduced as much as practicable,
and the temperature control of the resin is improved, and the
responsiveness of the temperature control is also improved. Thus,
this heating cylinder device for a molding machine minimizes
fluctuations in the system due to the motion of the resin material
which is being heated up, changes in the temperature of the resin
material, dissipation of heat in injecting the resin material, and
so on. Thereby, this heating cylinder device for a molding machine
promotes the production of more precise finished molded products,
by providing proper heat management by keeping the thermal
interference between neighboring ones of heating zones thereof as
low as possible, as well as by keeping the thermal interference
from outside sources as low as possible.
In FIG. 7, there is shown a sectional view of a heating cylinder
device 12 according to the fourth preferred embodiment of the
present invention, taken in a fashion similar to FIGS. 2, 5, and 6
in a sectional plane containing the axis of said heating cylinder
device; in FIG. 7, reference symbols like to those of FIGS. 1 and 2
relating to the first preferred embodiment and FIGS. 5 and 6
relating to the second and third preferred embodiments denote like
parts and zones. This heating cylinder device 12 again is for being
fitted into an injection molding machine like the machine 10 shown
in FIG. 1 relating to the first preferred embodiment, comprising a
hopper for charging the resin, the heating cylinder device 12, a
screw drive device for rotatively driving a screw piston 20
incorporated in said heating cylinder device 12 for injecting the
molten resin, and a movable plate drive device for removing the
molded products by opening and closing a metallic die which is
mounted between a fixed plate and a laterally movable plate; again,
this machine is not particularly shown in the figures, because its
construction may be substantially identical to that of the FIG. 1
machine.
The heating cylinder device 12, in this fourth preferred
embodiment, again is generally formed in a cylindrical shape with a
central axial hole 19 formed through a cylinder wall portion 18,
and with a screw piston 20 mentioned above fitted in said central
axial hole 19, so as when rotated in a certain direction by the
aforementioned screw drive device 13 to move to the left in the
figure into said hole 19 so as to apply compression force to resin
in said hole 19, and so as when rotated in the opposite direction
to said certain direction to be moved to the right in the figure
and to be withdrawn out of said hole 19. When said screw piston 20
is thus withdrawn from the hole 19 to a position beyond a certain
position, resin charged in the hopper 11 can travel downwards into
the hole 19 to recharge the heating cylinder device 12. A nozzle 21
is provided at the opposite end (the left end) of the heating
cylinder device 12 from the hopper 11 (which is at the right end).
Thus, as the screw piston 20 is alternately rotated in said certain
direction and in the opposite direction to said certain direction,
it is alternately forced into the hole 19 and withdrawn therefrom,
thus alternately compressing resin in said hole 19 and forcing it
out through the nozzle 21, and recharging said hole 19 with fresh
resin from the hopper 11.
In the heating cylinder device 12, as before in the devices of
FIGS. 2, 5, and 6, there are altogether defined five heating zones,
designated as Z1 through Z5, and axially spaced along the axis of
said heating cylinder device 12 from the right to the left as seen
in FIG. 7, i.e. from the end thereof at which the hopper 12 is
provided to the end thereof at which the nozzle 21 is provided.
Around each of these heating zones Z1 through Z5 there is fitted a
corresponding heater H1 through H5, and in the inner wall portion
of the heating cylinder device 12, in each of said heating zones Z1
through Z5, there is again fitted a corresponding thermocouple T1
through T5.
In detail, yet again, the first heating zone Z1 is the portion of
the heating cylinder device 12 into which the resin is supplied
from the hopper 11, and is heated by the heater H1 and is also
water cooled so that the resin may be supplied from the hopper 11
without any risk of its surface being melted. And the thermocouple
T1 detects the temperature in this first heating zone Z1. The
second heating zone Z2 is a portion of the heating cylinder device
12 in which the resin is, next, heated up substantially only by the
heater H2, and the thermocouple T2 detects the temperature in this
second heating zone Z2. The third heating zone Z3 is a portion of
the heating cylinder device 12 in which the resin is, next, heated
up both by the heater H3 and by the frictional heat generated by
the rotation of and by the compression effect generated by the
screw piston 20; and the thermocouple T3 detects the temperature in
this third heating zone Z3. The fourth heating zone Z4 is a
reservoir in which the resin material to be injected is received
for a certain time interval before being injected, and is required
to be kept at a certain high temperature; in this portion of the
heating cylinder device 12, the resin is heated up by the heater
H4, and the thermocouple T4 detects the temperature in this fourth
heating zone Z4. And the fifth heating zone Z5, which is just
before the nozzle 21, is a portion of the heating cylinder device
12 in which the resin is particularly subject to disturbance of its
temperature by external influences such as the heat capacity of the
metallic die 16 and the atmosphere; and, in order to eliminate such
external influencese, the resin in this fifth heating zone Z5 is
kept hot by the heater H5, and the thermocouple T5 detects the
temperature in this fifth heating zone Z5.
Now, as in the second and third preferred embodiments described
above, the wall portion 18 of the heating cylinder device 12 is
structured (however not with any annular circumferentially
extending grooves spaced apart along its longitudinal length) with
the outer diameters of the parts of the wall portion 18 of the
heating cylinder device 12 which define the first heating zone Z1,
the second heating zone Z2, the third heating zone Z3, and the
fourth heating zone Z4 all being substantially the same; while as
before the outer diameter of the wall portion 18 of the heating
cylinder device 12 at the fifth heating zone Z5 is much smaller
than at all the other heating zones Z1 through Z4. Thus, the
portions of the wall portion 18 which define the heating zones Z1
through Z4 are each of approximately the same thickness, in this
fourth preferred embodiment. However, particularly according to the
particularly specialized inventive concept of fourth preferred
embodiment of the present invention, all of the first through the
fifth heaters H1 through H5 are as in the first preferred
embodiment of FIG. 2 formed as bands extending right around the
cylinder of the heating cylinder device 12, so that the four
heaters H1 through H4 are not buried deep within the wall portion
18 of said heating cylinder device 12, as was the case in the third
preferred embodiment shown above; and around the first heater H1
there is provided no particular layer of insulating material, while
around the second, third, and fourth heaters H2, H3, and H4 there
is provided a first layer 28' of insulating material, around the
third and fourth heaters H3 and H4 there is further provided a
second layer 39 of insulating material on top of said first layer
28', and around the fourth heater H4, only, there is yet further
provided a third layer 30 of insulating material on top of said
first layer 28' and said second layer 39. And in the shown
particular construction, although this is not intended to be
limiting, all these layers 28', 29, and 30 of insulating material
are of substantially the same thickness. A suitable material for
use as this insulating material is glass wool. In other words, the
first heater H1 for the first heating zone Z1 is not wrapped with
any insulating material layer, the second heater H2 for the second
heating zone Z2 is wrapped with one layer of insulating material,
the third heater H3 for the third heating zone Z3 is wrapped with
two layers of insulating material, and the heater H4 for the fourth
heating zone Z4 is wrapped with three layers of insulating
material, so that the thickness of the insulating material provided
for each zone corresponds to the heat capacity required for that
zone. I.e., the heat capacities of the various heating zones Z1
through Z4 are adapted to the respective temperatures at which they
are required to operate. That is, the insulation is omitted in the
case of the first and the fifth heating zones Z1 and Z5, in which
it is required to transfer the controlled temperature of the
respective heaters Hl and H5 to the resin material, so as to reduce
their heat capacities, while on the other hand in the case of the
fourth heating zone Z4, which is required to be maintained at a
certain temperature, a thick layer of insulating material is
provided, in order to make its heat capacity high; and the cases of
the second and third heating zones Z2 and Z3 are intermediate
between these two extremes.
This heating cylinder device 12 according to the fourth preferred
embodiment of the present invention may be controlled by a control
system similar to that described above with reference to FIGS. 3
and 4 with respect to the first preferred embodiment; details are
again omitted herein in the interests of brevity of
description.
Thus, by providing the layers of insulating material for the three
heaters H2 through H4, and by determining the thicknesses of said
layers in consideration of the heat capacities required for proper
temperature control of the respective heating zones Z1 through Z5,
or in other words by considering the responsiveness of the
temperature control, in addition to temperature controlling the
respective heating zones Z1 through Z5, the influences of thermal
interferences between the heating zones Z1 through Z5 may be
eliminated, and the responsiveness of the control system is
improved, whereby fluctuations of the temperature of the resin
which is to be forwarded to the fifth heating zone Z5 and to the
nozzle 21 may be kept minimal.
Thus, also according to this fourth preferred embodiment of the
present invention, there is provided a heating cylinder device for
a molding machine which can keep the injection cycle of the machine
short, thus improving the productivity of the machine and reduces
the cost of operation and thus the cost of the finished products.
Further, the power consumption is reduced as much as practicable,
and the temperature control of the resin is improved, and the
responsiveness of the temperature control is also improved. Thus,
this heating cylinder device for a molding machine minimizes
fluctuations in the system due to the motion of the resin material
which is being heated up, changes in the temperature of the resin
material, dissipation of heat in injecting the resin material, and
so on. Thereby, this heating cylinder device for a molding machine
promotes the production of more precise finished molded products,
by providing proper heat management by keeping the thermal
interference between neighboring ones of heating zones thereof as
low as possible, as well as by keeping the thermal interference
from outside sources as low as possible.
Although the present invention has been shown and described with
reference to the preferred embodiments thereof, and in terms of the
illustrative drawings, it should not be considered as limited
thereby. Various possible modifications, omissions, and alterations
could be conceived of by one skilled in the art to the form and the
content of any particular embodiment, without departing from the
scope of the present invention. For example, although the various
embodiments of the present invention which have been shown are all
directed to its application to an injection molding machine, the
present invention is not to be considered as limited to such an
application. Therefore, it is desired that the scope of the present
invention, and of the protection sought to be granted by Letters
Patent, should be defined not by any of the perhaps purely
fortuitous details of the shown preferred embodiments, or of the
drawings, but solely by the scope of the appended claims, which
follow.
* * * * *